The invention generally relates to wireless code division multiple access communication systems. In particular, the invention relates to receiving user signals in such systems.
FIG. 1 is an illustration of a simplified wireless code division multiple access communication system. Each base station 201-204 (20) communicates with user equipments (UEs) 221-2221 (22) in its cell 241-242. To illustrate as shown in FIG. 1, base station 201 communicates with UEs 221-229 in its cell 24.
Each cell 24 may also be divided into sectors 261-266 (26), such as six sectors 26 as shown in FIG. 1. Typically, the base station 20 communicates with each sector 26 using one or multiple antennas assigned to that sector 26. Each UE 22 in a sector 26 communicates with that sector""s antennas.
The distribution of UEs 22 in a cell 24 and sector 26 as well as cell and sector loading may vary. FIGS. 2a, 2b and 2c illustrate varieties in a cell and sector loading. FIG. 2a illustrates a lightly loaded three sector cell with even distribution. The UEs 22 in each sector 26 are relatively even. FIG. 2b illustrates a lightly loaded cell 24 with uneven UE distribution. One sector 263 has no users (no UEs) and one sector 262 has many users. FIG. 2C is a heavily loaded cell 24 with uneven distribution. One sector 263 has a few users and other sectors 261 and 262 have a large number of users. The base station/Node-B receiver preferably needs to accommodate all of these various loadings.
Furthermore, a UE 22 may move between sectors 26, such as from sector 262 to sector 261, as shown in FIG. 3. One approach to transfer the handing of the UE 22 between the two sectors 261 and 262 is softer handover. In softer handover, during the transition period, the UE 22 communicates with the antennas"" of both sectors 261 and 262 simultaneously. To improve signal quality during softer handover, it is desirable for the Node-B/base station receiver to accommodate the combining of the communications received by each sector 26.
Accordingly, it is desirable to have a Node-B/base station receiver capable of handling these varying conditions.
A Node-B/base station receiver comprises at least one antenna for receiving signals. Each finger of a pool of reconfigurable Rake fingers recovers a multipath component of a user and is assigned a code of the user, a code phase of the multipath component and an antenna of the at least one antenna. An antenna/Rake finger pool interface provides each finger of the Rake pool an output of the antenna assigned to that Rake finger. A combiner combines the recovered multipath components for a user to produce data of the user.